Dude, you give communism a bad name. Sure, each in that system contributes with his "abilities", then receives what he "needs", but remember that abilities here doesn't mean money, it means mental and physical. Only a disabled, child, woman, or elder wouldn't be able to contribute "as much" in a communist system, but nearly everyone else can give his max. It's not a free-loader system, far far far from it.
The problem with communism is there's no incentive to work. If I make the same working 80 hours a week that I do working 1 hour a week then why the hell would I work 80 hours a week? Its human nature. Bitcoins have value because of the work it takes to create them. If you get the same value no matter how much work you put in then no one will put in work.
Communism gives communism a bad name.